Tag Archives: Theory of Science & Methodology

RCTs — the danger of imposing a hierarchy of evidence The imposition of a hierarchy of evidence is both dangerous and unscientific. Dangerous because it automatically discards evidence that may need to be considered, evidence that might be critical. Evidence from an RCT gets counted even if when the population it covers is very different from the population where it is to be used, if it has only a handful of observations, if many subjects dropped out or...

 [embedded content] Great lecture by one of my favourite philosophers of science. Among other things, Nancy Cartwright underscores the problem many ‘randomistas’ end up with when underestimating heterogeneity and interaction is not only an external validity problem when trying to ‘export’ regression results to different times or different target populations. It is also often an internal problem to the millions of regression estimates that economists produce every year....

RCTs — assumptions, biases and limitations Randomised experiments require much more than just randomising an experiment to identify a treatment’s effectiveness. They involve many decisions and complex steps that bring their own assumptions and degree of bias before, during and after randomisation … Some researchers may respond, “are RCTs not still more credible than these other methods even if they may have biases?” For most questions we are interested in,...

1855 — the birth of causal inference  [embedded content] If anything, Snow’s path-breaking research underlines how important it is not to equate science with statistical calculation. All science entail human judgement, and using statistical models doesn’t relieve us of that necessity. Working with misspecified models, the scientific value of statistics is actually zero — even though you’re making valid statistical inferences! Statistical models are no...

Wann Wissenschaft wahr ist  [embedded content]

The limits of extrapolation in economics There are two basic challenges that confront any account of extrapolation that seeks to resolve the shortcomings of simple induction. One challenge, which I call extrapolator’s circle, arises from the fact that extrapolation is worthwhile only when there are important limitations on what one can learn about the target by studying it directly. The challenge, then, is to explain how the suitability of the model as a...

Do economic models actually explain anything? One of the limitations with economics is the restricted possibility to perform experiments, forcing it to mainly rely on observational studies for knowledge of real-world economies. But still — the idea of performing laboratory experiments holds a firm grip of our wish to discover (causal) relationships between economic ‘variables.’ If we only could isolate and manipulate variables in controlled environments, we...

Les théorèmes d’incomplétude de Gödel  [embedded content]

What properties do societies possess that might make them possible objects of knowledge for us? My strategy in developing an answer to this question will be effectively based on a pincer movement. But in deploying the pincer I shall concentrate first on the ontological question of the properties that societies possess, before shifting to the epistemological question of how these properties make them possible objects of knowledge for us. This is not an arbitrary order of...

Minimal realism — much ado about nothing To generalise Mäki’s distinction between realism and realisticness, someone who believes that economic theories must or should include unrealistic assumptions is not necessarily a non-realist in the broader sense of philosophical realism: “A realist economist is permitted, indeed required, to use unrealistic assumptions in order to isolate what are believed to be the most essential features in a complex situation …...